WATCH: Time lapse shows raising of Costa Concordia

GIGLIO, Italy (CNN) – The capsized cruise liner Costa Concordia was sitting upright early Tuesday after the first step of an unprecedented effort to salvage the ill-fated ship.

In a lengthy process involving massive pulleys, cables and steel tanks, a salvage crew managed to roll the 114,00-ton vessel off the rocks where it ran aground 20 months ago.

“It was a perfect operation, I would say,” said Franco Porcellacchia, the head of the technical team for the cruise line Costa Crochiere, owned by American firm Carnival Cruises.

The effort began at 9 a.m. Monday (3 a.m. ET). By midnight, despite delays for thunderstorms and for slack in a crucial cable, the ship had been hauled off the rocks and upward about 25 degrees — far enough to start drawing water into the massive steel boxes attached to the exposed side of the hull, using the weight of that water to finish rolling the hulk onto a steel platform built off the sea floor.

Four hours later, the wrecked ship came to rest on the platform, said Franco Gabrielli, the head of Italy’s Civil Protection Authority. Once righted, it sported a slashing, diagonal line separating the white paint of the exposed hull from the brownish muck that had collected on its submerged starboard side.

“The sides of the ship will need major work and repair, but today we have really taken a clear step to allow the ship to be taken away,” Gabrielli said.

A great deal of work remains, Gabrielli cautioned. A tiny robotic submarine with surveillance cameras will survey the damaged side of the ship and create models needed in planning for the next phase of operations — the attachment of more sponsons to the starboard side.

Once those are installed, water will be pumped out of the sponsons to refloat the vessel. Organizers expect the ship won’t be towed away for dismantling until summer of 2014.

“We will have a lot of things in the next few days to understand what needs to done to bring this venture to a conclusion,” Porcellacchia said.

But Tuesday’s predawn announcement was met with applause from the people of Giglio, a tiny island that was transformed by the disaster.

“We have achieved a big goal. We are not at the end of the operation, but this is a very important achievement,” Giglio Mayor Sergio Ortelli said.

No sign of lost victims’ remains

The Costa Concordia ran aground off Giglio in January 2012, killing 32 of the 4,200 people on board. The remains of two victims, Russel Rebello of India and Maria Grazia Trecarichi of Sicily, never have been recovered.

Rebello, 33, was a cruise waiter who was last seen helping passengers off the ship. Trecarichi was on the cruise to celebrate her 50th birthday with her 17-year-old daughter, who was one of thousands of people who survived the deadly shipwreck.

Once the ship was off the rocks, operators sent robotic cameras to survey the damage but found no sign of bodies. But there also appeared to be no sign of leaks, Franco Gabrielli, the head of Italy’s Civil Protection agency, told reporters — a promising sign, as the wrecked liner is full of spoiled food and chemicals including paint and lubricants.

The nearly $800 million effort is the largest maritime salvage operation ever, according to Costa Crochiere and its partners, Florida-based Titan Salvage and the Italian marine contractor Micoperi. Reporters and sightseers lined the port and the hillsides to watch as the work began.

A complex process

Monday’s process, known as parbuckling, was the first step in a plan to remove and scrap the 952-foot ship. The Concordia was rotated onto giant platforms 30 meters (about 98 feet) below the water level, which leaves parts of the ship that have been dry for months submerged and filled with water.

No ship this large or heavy had never been parbuckled before. Normally, crews would have blown up the ship or taken it apart on site — a cheaper route than what’s being done now.

But officials say that wasn’t an option with the Costa Concordia, because the ship is filled with noxious substances and because there are two bodies still believed to be either trapped beneath the ship or somewhere deep in its hull.

Technicians and salvage managers were watching closely to see what goes wrong and what works.

“It will set the new standard for maritime salvage,” Giovanni Ceccarelli, the project’s engineering manager, told CNN.

Hundreds of people and dozens of companies have collaborated on the preparations, but the parbuckling came down to 12 people, including salvage master Nick Sloane and specialized technicians, who guided the operation from inside a prefabricated control room set up on a tower on a barge in front of the ship.

In preparation for Monday, tall towers had been anchored onto the rocky shoreline between the ship and the island have been fitted with computer-operated pulley-like wheels.

When the rotation began, the wheels guided thick cables and chains pulling the middle third of the ship from under its belly toward Giglio. At the same time, more chains and cables attached to the sponsons welded onto the ship’s port side pulled the ship from the top toward the open sea.

Noxious substances, other items on board

If things had gone wrong, it could have been disastrous. The ship contains a mix of chemicals that would be devastating for the environment if leaked into the water, which would happen if the ship breaks apart or sinks.

The ship carried thousands of liters of thick lubricants, paints, insecticides, glue and paint thinners before it crashed. There are also 10 large tanks of oxygen and 3,929 liters of carbon dioxide aboard.

That’s not all.

Refrigerators filled with milk, cheese, eggs and vegetables have been closed tight since the disaster.

And the freezers that have not burst under the water pressure are still locked with their thawed, rotting contents sealed inside, including 1,268 kilograms of chicken breasts, 8,200 kilograms of beef, 2,460 kilograms of cheese and 6,850 liters of ice cream.

But as the ship rotates, much more water will enter it than will spill out, salvage operators say. That fresh seawater will dilute some of the toxic mix, but it will all eventually have to be purified and pumped out before the ship is towed across the sea for dismantling.

In the meantime, the salvage operators have set up two rings of oil booms with absorbent sponges and skirts that extend into the water to catch any debris that may escape. Now that the ship is upright, it will be months before the contents are removed, probably not until it reaches its final port.

At that time, Costa officials say they intend to remove personal effects from the staterooms and return those to each passenger, no matter how soggy. None of that is expected to happen before next summer.

Meanwhile, Francesco Schettino, the captain who guided the ship off course, faces charges of manslaughter, causing a maritime disaster and abandoning ship with passengers still on board. His trial resumes in Grosseto on September 23.